This invention relates in general to radio communications systems. More particularly, the invention relates to radio paging systems.
In the past several years, radio paging technology has advanced from the rather simple tone-only pager (tone alert only, no voice), to the tone and voice pager (tone alert with a voice message) and more recently to the numeric and alphanumeric display pagers. In a typical conventional numeric or alphanumeric display paging system such as that shown as system 10 in FIG. 1, a central transmitter or paging terminal 20 is used to generate the radio pages which are transmitted via a radio link to a fleet of paging receivers 1, 2, 3 . . . N, wherein N is the total number of pagers in system 10. A unique digital address is associated with each of paging receivers 1, 2, 3 . . . N. A page which is transmitted by paging terminal 20 consists of the unique digitally encoded address of the particular pager to which the page is targeted, immediately followed by a corresponding digitally encoded numeric or alphanumeric page message which is intended for display on the target pager.
Typically, the numeric or alphanumeric page message is stored in a memory within the paging receiver for later recall and display by the pager user. Paging receivers are available with a wide range of message storage capabilities which range from the ability to store just a few rather short numeric page messages to the ability to store a relatively large number of longer alphanumeric page messages.
However, conventional display paging systems are generally one-way systems. That is, the user receives a paging message from the central terminal but has no way of responding to that message with his or her pager. Instead, the pager user must seek out a telephone or other means of responding to the originator of the paging message. Such systems also do not provide a method for efficiently mixing acknowledge back and non-acknowledge back pagers on a common channel; and such systems do not efficiently allow variable data types and variable message lengths to be intermixed with acknowledge back and non-acknowledge back pagers.